<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    let arr = [1,2,3,4,5,6,7];

    //计算数组元素的和
    // let total = arr.reduce((prev, current) => {
    //   return prev + current;
    // });

    let total = arr.reduce((prev, current) => prev + current);

    console.log(total);

  </script>
</body>
</html>